Neither I nor other Vodafone managers or employees at any time made financial offers or incentives to Mannesmann employees

Chris Gent, Vodafone

Mr Gent is currently under investigation in Germany for corruption resulting from his firm's takeover last year of Mannesmann, whose board awarded then-chief executive Klaus Esser a 30.6m euro (�19m; $28m) golden handshake.

The board also gave large compensation packages to about 20 other senior Mannesmann staff.

Mr Gent told Mannesmann's annual general meeting that the payments were wholly proper.

"Neither I nor other Vodafone managers or employees at any time made financial offers or incentives to Mannesmann employees," Mr Gent said.

Co-operation promise

Mr Gent told Mannesmann shareholders that he would co-operate with the investigation, and said he was confident that they would clear him and his firm.

At the same time, Mr Esser, who now works for an American financial company, also went on the defensive.

Mr Esser called on the authorities to bring the investigation to a swift conclusion, since the main allegation - that the payments came from Vodafone - had not been proven.

"As soon as the truth has been proven, then the investigation must be brought to an end," he told German magazine Wirtschaftswoche.

Vodafone's shares fell on Wednesday, closing down 2.5p at 130.5p.

Bid battle

The bonus allegations concern Vodafone's takeover of Mannesmann, which board members at the German firm agreed to in February last year, ending a bitter battle to see off the bid.

German prosecutors are investigating whether there is sufficient evidence to level formal charges over claims that the bonuses were used as a sweetener to Vodafone's bid.

Hong Kong conglomerate Hutchison Whampoa briefly owned part of Mannesmann, before selling out to Vodafone.

"It was money paid by the Hutchison management to reward the Mannesmann management [for prior performance]," Financial Times Deutschland editor-in-chief Kristof Keese told the BBC's World Business Report.

"What German investigators now think is that the entire thing had something to do with the Vodafone deal. It is under scrutiny because investigators believe the money was only technically paid by Hutchison but in fact came from Vodafone," he said.